Vat assistant for use in dyeing



Patented Nov. 18, 1930 UNITED STATES PATENTOEFlCE JEAN GEORGES ANDCHARLES J. SALA, OF WILMINGTON, DELAWARE, ASSIGNOBS TO E. I. DU PONT DENEMOURS & COMPANY, 01'' WILMINGTON, DELAWARE, A COR- PORATION OFDELAWARE VAT ASSISTANT FOR USE IN DYEING No Drawing. Application filedAugust 4, 1927. Serial No. 210,715.

It is essential that: all during the dyeing- This invention relates tothe art of dyeing operation the dye be kept in its most highly and moreparticularly to the preparation and application to cellulose orartificial silk fabrics of a dyeing 'bath containing a material adaptedto facilitate the dyeing operation. The invention also relates to thedyeing liquor and to the fabric dyed therewith as articles ofmanufacture.

As is well understood in the art, by the term vat dye is meant acoloring matter insoluble in water but which can be convertedon'reduction into a so-called leuco-compound which is soluble to acertain extent'in solutions of alkali. Such vat dyes are characterizedby their excellent fastness but the diificulty of dyeing themsatisfactorily with fair yield has been a drawback to their use in thisconnection. One of the objects of the present invention is to overcomethis difficulty in the manner described in detail below.

In dyeing with vat colors ascarried out at present several processes arefollowed:

1. On iece goods.

(1. igger dyeing method.

b. Padding method in reduced bath.

0. Padding method in unreduced bath with subsequent development of thedye in jigger. This rocess is the most usually adopted.

2. Dyeing of raw-stock, unspun cotton, in

machine. I

3. Dyeing of yarn on beams or packages in machines.

In general this invention relates in all or some of its improvements tothe operation of d eing cotton or artificial silk. fibres in any 0 theseways. I w

Most of these processes require the use of a reduced bath. To undergothis operation the vat dyestufl is generally passed through a finescreen (200 mesh/inch) diluted some-.

what with water and added to the dyebath containing a correspondingamount of alkali and a reducing agent such as sodium hydrosulfite, whichis the most commercially used.

The tem era-ture is raised for this purpose to a suita le pointaccording to the particular vat dyestuff used and when complete reduction is reached the dyeing operation is started.

dispersed state.

Therefore, it is first of all important that the dyestufl paste be ofspecial fineness but even with the finest pastes at present in commercea great deal of color is lost because of its failure to dye the fibre.This wasted dyestulf is, in many cases not taken up by the fibre, andwashes off during the soaping operation which follows the dyeing. Also,in most cases the great affinity of the reduced dyestufi itself for thefibre is a handicap to producing even dyeings.

,Now we have found, however, that certain organic compounds, when mixedeither with; the dyestufi paste or when dissolved in the dyebath,produce Various improved results. These organic compounds are not inthemselves new but it is believed that the use of them for this'purposeis entirely new. The compounds we employ are substituted aliphaticamines containing hydroxyl groups in the aliphatic radicals. They arevery strong-' R R representin either an a 1 cup C H(2 +1) hydrogem or ahydroxy a l k yl goup It makes lpo difference. whether R is hydrogenwhile is an alkyl group or R is hydro en and R an alkyl group. Also anyone 0 these substituents alread described may be' replaced by a compouncontaining the group GQH (OH) In carrying our invention into effect wecan proceed in two wa s.

1. We may mix the ingredient adopted to facilitate the dyeing operationinto the vat color paste, dilute somewhat with water, and pass thissuspension through a screen as described above. This suspension which isve highly dispersed is then added to the dyebat containing thealkali'and the reducing agent;

The temperature is then brought to about the appropriate dyeingtemperature at the start. A complete reductlon followed by a completesolubilization of the leuco is the result. The chemical process is notessentially different from one method to the other, except whenpad-method is used. In this case the unreduced dyestufi is mixed withthe assistant as outlined above then diluted to a certain concentrationwith water, gum and oil, the material padded therewith and dried andlater developed on a jigger in a solution as described above andcomposed of alkali and a reducing agent. Additional dyestufi' may or maynot be added in this case.

After the dyeing operation which takes about 45 minutes the material isrinsed and treated with an oxidizing agent such as bichromate of soda,or preferably perborate of soda, rinsed and thoroughly soaped, thenagain rinsed, allowed to dry and finished.

The presence of the new assistant very effectively aids the transfer ofthe dye to the cotton and a number of advantages are obtained.

2. We may also use the vat color pastes prepared in the manner describedin our copending application, Serial No. 167,066,

- which pastes already contain the new assistant, the dyeing processbeing hence not different from the ordinary vat color dyeing processes,with the exception that the results are obtained as according to thepresent invention.

In order fully to disclose our process the following examples of typicaldyebaths and methods are furnished. 4

It is to be understood, however, that these examples are onlyillustrative and that the conditions, proportions and reagents specifiedtherein may be varied within wide limits, that is EXAMPLE I An 8 shadeof Ponsol blue GD (Schultz #842) on 150 lbs. of mercerized cotton piecegoods is obtained as follows: 12.75 lbs. of Ponsol blue GD (Schultz#842) are mixed with 8.16 lbs. of the new dye assistant 1 gal. of coldwater added and the suspension passed through a fine screen. A perfectspeckless paste is so obtained which is added to the jigger dyebath,composed of the following: lbs. caustic soda lbs. hydrosulfite conc. 10lbs. added immediately, 5 lbs. after 1 passage. 100 gals. water.

The temperature raised to 110 F., and after complete reduction thedyeing started at this temperature. The temperature is then allowed torise during 30 minutes to 125 F., and further dyed at this temperaturefor 10 to 15 minutes. Then give I wash, 4 passages in sodium perborate,2 lbs. per 100 gals. at 120 F., 2 cold washes, 5 passes in boiling soapsolution 3 lbs. soap to 100 gallons, then rinse and wash in the open,dry and calender.

When using the dyestuif pastes according to our co-pending application,Serial No. 167,066, where the assistant is already in the color paste,the foregoing example is simplified to the extent indicated by thefollowing process.

EXAMPLE II An 8 shade of Ponsol blue GD pre- I 10 lbs. caustic soda(dry) 15 lbs. sodium hydrosulfite to 100 gallons bulk and the dyeingprocess carried out as described above.

EXAMPLE III Paddingdigger dyeing method The padding liquor is composedof:

5 lbs. Ponsol blue GD prepared according to said co-pending case andcontaining 64% of the new assi-stant.

11 gals. water 8 ozs. gum tragacanth 5 lbs. bleaching oil 12% gallonsbulk The squeeze of the pad roller is about 60%.

The padded material is then dried and developed in a jigger according tothe process of Example II above, by adding an additional quantity of thedyestufl paste so as to have an 8 dyeing.

The developing bath contains the same ingredients in the same quantitiesas under Example II, the dyeing being carried on underthe sameconditions. This process oiiers the advantage of better penetration and1s usually adopted in the mills. p

This process may be changed also as follows:

EXAMPLE IV The pad liquor is composed of: 5 lbs. Ponsol blue GD (Schultz#842) EXAMPLE V Package process:

% shade of Ponsol dark blue BR (Schultz #763) or violet RRD (Schultz #766) The boiled ofl' yarn is dyed in the package machine with 5% of vatcolor paste 3% sodium hydrosu 3% assistant water y The conditions ofdyeing are the same as usual After d eing rinsr and oxidize with 2%sodium perh 2 caustic soda (drlyh) If the vat color pastes preparedaccording to our co-pending case above are used, the

above formula is modified as follows: 5% dyestuff prepared according tosaid copending application. 2%% caustic soda 3% sodium hydrosulfiteater' The shades come out bright and very even.

It is obvious that the preparing of the dye liquors from all theingredients used may be varied by the dyer.

Advantages and results from the use of these assistants, either bydirect addition to the dyebath or by preliminary addition to the vatdyestufi' pastes:

1. The exhaust of these dyebaths are much better than those used atpresent, which accounts for an i creased yield in depth of 2. The effectof the assistant as an excellent solvent is shown in slowing down therate at which the dye goes on, which results in equalizing the depth ofdyeing giving, in

this way, extremely even results. 7 This is of very great advantage fordyes having great afiinity such as blue GD, violet'RR blue 3 BCS, darkblue BR, etc.

3. The fixation of the dyestufl' is improved over the results of theusual methods, therefore, on s'oaping in .a boiling soap solutionthedyestufi' loses less which accounts for an increased yield in shade(depth).

4..Due to brilliancy of the dyeing is enhanced.

5. It. is well known that most of the dyes,

. when being treated with a soap solution change considerably in shade.This is the case, for example, with the indanthrene blues (Schultz #842)but when dyed according to this method, additional soaping does notchange the shade to any noticeable extent.

6. The addition of the assistant to the dyestuff paste puts the latterin a perfectly dispersed condition permitting a much quicker screening(several hours economy in time) I and permitting the padding of speckfree paste which is of enormous value is specky dyeings orate, rinse,soap, rinse andmg with the vat color perfect dyeing conditions the anabsolutelytion causes the dyer considerable trouble which is avoided bythis invention.

8. The addition or presence in the vat paste 6 of such assistant isparticularly of great assistance when dyeing with vat dyestufl's of thevery insoluble type such as the highly chlorinated indanthrene blues,etc. It always insures a perfect solution, regulatesthe exhaust'andresults in a very level (1 eing.

As many apparently widely di erent embodiments of this invention may bemade without departing from the spirit thereof, it is to be understoodthat we do not intend to limit ourselves to the specific embodimentsthereof except as indicated in the appended claims.

We claim: 1. The processof improving a vat color paste, the step whichcomprises incorporating with the vat color paste a compound having thestructural formula:

group O IL h drogen, or the hydroxy alkyl group C H gH.

he process of improving a vat color paste, the step which comprisesincorporating with the vat color paste a compound of the type describedin claim 1, in which compound C H OH represents the radical C H OH.

3. The process of improving a vat color paste, the step which comprisesinco rating the structural formula: 1

.Ha- N- l R- wherein' C.H,,,OH represents an aliphatic: 'radical,substituted or not, and R and R,

represents either hydro en or an aliphatic radical or a hydroxy-ahphaticradical.

4. The. process of improving a vat color paste, the step which comprisesincorporatmg with the vat color paste a compound of the type describedin claim 3, wherein R represents a hydro -aliphatic radical.

5. The process 0 improving a vat color paste, the step which comprisesincorporatmg with the vat color paste a compound'of the type describedin claim 3, wherein IL wherein R R, represents" either the alkyl pasteacompoun havalkyl group canon represents a hydroxy-aliphatic radical andR represents hydrogen.

6. The process of improving a vat color paste, the stepwhich comprisesincorporating with the vat color paste a compound of the typedescribed'in claim 3, wherein R re resents hydrogen.

The process of improving a vat color paste, the step which comprisesincorporating with the vat color paste a compound of the type describedin claim 3, in which -compound both C H OH and R represent the radical(LI-LOH.

8. In the process of dyeing with vat colors, the step which comprisesincorporating in the vat a compound having the structural formula onnhonwherein R R represents group C H hydrogen,

either the alkyl or the hydroxy 9. In the process of dyeing with vatcolors, the step which comprises incor orating in the vat a compound ofthe type escribed in claim 1, in which compound C 0 represents theradical 0 11 011.

10. In the process of dyeing with vat colors, thestep which formula OHInOH -R1 \R|- 1 wherein C H OI-I represents an aliphatic radical,substituted or not, and R and R represents either hydrogen or analiphatic radical or a hydroxy-ali hatic radical.

11. In the process of yeing with vat colors, the step which comprisesincorporating in the vat a compound of the type described in claim 3,wherein R represents a hydroxyaliphatic o radical.

12. In the process of dyeing with vat colors, the step which comprisesincorporating in the vat a compound of the type described in claim 3,wherein R represents a hydroxyaliphatic radical and R representshydrogen.

13; In the process of dyeing with vat colors, the step which comprisesincorporating in the vat a compound of the type described in claim 3,wherein R represents hydrogen.

14. In the process of dyeing with vat colors, the step which comprisesincorporating in the vat a compound of the type described in claim 3, inwhich compound both C H OH and R represent the radical C I-LOH.

In testimony whereof we aflix our signalures.

J EAN GEORGES KERN. CHARLES J. SALA.

comprises incorporating in the vat a compound having the structuralCertificate Cerrect ion Granted November 18, 1930, to

Patent No. 1,782,122. I

JEAN GEORGES KERN ET AL.

' It is hereby, certified that error appears in the printedspecification 0f the above numbered patentqeqniri-ng correction asfollows: Page 1, line 90, strike out the formula and insert instead C H(OH) 5 page 3, lines 115 150117, strike out the formula and insertinstead -NR and that the said Letters Patent should be read I 2 4 v withthese corrections-therein that the same may conform to the record of thecase in the Patent Oflice.

Signed and sealed this 23d day of December, A. D. 1930.

[SEAL 7 I 1 a s M. J.'MOOR-E,

Acting Commissioner of Patents. I

